function [tau, w] = getGroupDelay (ceros, polos, wmax)

tau=zeros(1,1000);
w=logspace(-1,ceil(log10(wmax)),1000);
if ceros~=-1
for k=1:length(ceros)
    sigma=real(ceros(k));
    beta=imag(ceros(k));
    if sigma==0 && beta == 0
        tau=tau + pi/2;
    else
        tau= tau + sigma./(sigma^2+ (beta-w).^2);
    end
end

end
if polos~=1
for k=1:length(polos)
    sigma=real(polos(k));
    beta=imag(polos(k));
    if sigma==0 && beta == 0
        tau=tau - pi/2;
    else
    tau= tau - sigma./(sigma^2+ (beta-w).^2);
    end
end
end
end
